The present invention relates to hoists and the like and more particularly to an improved arrangement for automatically operating a brake on a windlass thereof to prevent unwanted reverse rotation of said windlass, such as when it is desired to maintain a load in an elevated or other position in opposition to the reverse rotational force applied to the windlass by such load.
Hoists are widely used to lift and support loads of various kinds. For example, hoists find wide usage in automobile garages and the like for lifting and supporting heavy automobile parts, e.g., engines. Most hoists are basically block and tackle arrangements, some of which simply require manual input of energy for operation, and others which are motor driven. It will be recognized that if a hoist is going to be used to support a load in an elevated position as well as to lift such load, means of one sort or another must be provided for assuring that the hoist does not allow the load to lower, except when desired. Because unwanted and unexpected lowering of a load might result in injury to personnel in the vicinity, safety alone requires such a braking arrangement.
Various types of such a braking arrangement have been provided in the past ranging from, for example, mechanical ratchet and pall stopping apparatuses in hand operated hoists to disc brake arrangements in motor driven hoists. The difficulty with such arrangements now available, however, is that in general they do not automatically operate in response to a load being applied to the windlass. In this connection, some require operation by an operator. Others, such as the disc brake arrangements found on motor driven hoists rely for actuation to lack of rotation of the windlass, rather than on whether or not there is a load on such windlass. Whichever kind, because they do not react automatically in response to a load being present on the hoist windlass, they have proven unreliable at times. Moreover, those arrangements which are the most reliable tend to be quite expensive.